Application Of Colorimetric Sensing Platform Based On Paper And TiO₂ NTs In The Analysis Of Alkaline Phosphatase Activity

In recent years,colorimetric sensor analysis has become one of the research hotspots in the fields of biochemical analysis,environmental monitoring,disease prevention and control,food safety and so on,because of its many advantages such as simple equipment,low preparation cost and on-site detection.Especially the solid colorimetric sensor,because of its good portability,storage and large-scale commercial advantages,has an optimistic development and application prospects in various analytical fields.In this paper,two kinds of materials,filter paper and titanium dioxide nanotube arrays(TiO2NTs),were selected as the substrates to construct a colorimetric sensing platform for the detection of alkaline phosphatase(ALP)activity,and applied to the analysis of alkaline phosphatase activity in serum.In the first part,visual colorimetric sensing analysis and sensing materials.The development and application of paper-based colorimetric sensing platform,and the preparation and application of TiO2 nano-membrane.In the second part,a paper-based colorimetric plate for ALP activity analysis was developed.Firstly,paper-based nanocomposites loaded with titanium dioxide nanoparticles(TiO2NPs)were prepared by hydrothermal method.Then hydrophilic colorimetric pore was prepared by modifying with hydrophobic agent octadecyl phosphate(ODPA)and combining with photocatalytic properties of TiO2.The colorimetric sensing system uses zincon-zinc ion chelate(ZC-Zn2+)as the color probe.Because of the stronger affinity between pyrophosphate(PPi and Zn2+),zinc ions are extracted from the chelate,thus zincon shows the color when it is uncoordinated.In the presence of ALP,PPi is hydrolyzed into phosphate(Pi),which prevents the competition between PPi and ZC.Competition for coordination makes the colorimetric region still present the color of ZC-Zn2+chelate.The change of color in the colorimetric region can be directly analyzed by the naked eye,and more precise quantitative analysis can be carried out by means of color analysis software.In the third part,a colorimetric sensing membrane of TiO2NTs for ALP activity analysis has been developed.Based on the high radial ratio,visible light permeability and photocatalytic activity of TiO2NTs,a colorimetric sensing microarray based on TiO2NTs membrane was constructed,using TiO2NTs as a colorimetric sensing platform and zincon-zinc ion chelate(ZC-Zn2+)as a colorimetric probe for the analysis of ALP activity.Compared with paper chromogenic substrate,the color sensing membrane of TiO2NTs simplifies the experimental steps,improves the detection sensitivity and reduces the detection limit.